├── .clang-format ├── .gitignore ├── HACKING.md ├── LICENSE.txt ├── Makefile.am ├── README.md ├── autogen.sh ├── configure.ac ├── m4 ├── ax_cxx_compile_stdcxx.m4 └── ax_cxx_compile_stdcxx_11.m4 └── src ├── Makefile.am ├── aslr.cc ├── aslr.h ├── exc.h ├── ptrace.cc ├── ptrace.h ├── pyframe.cc ├── pyframe.h ├── pystack.cc ├── pystring.cc ├── pystring.h ├── symbol.cc └── symbol.h /.clang-format: -------------------------------------------------------------------------------- 1 | BasedOnStyle: Google 2 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | Makefile 2 | src/pystack 3 | -------------------------------------------------------------------------------- /HACKING.md: -------------------------------------------------------------------------------- 1 | Code contributions from all parties are welcome! 2 | 3 | All of the code in this project is formatted by clang-format. There's a file 4 | called `.clang-format` in the root of this project that should configure 5 | clang-format correctly. 6 | 7 | Pystack is free software, distributed under the terms of the GPLv3. 8 | -------------------------------------------------------------------------------- /LICENSE.txt: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. We, the Free Software Foundation, use the 18 | GNU General Public License for most of our software; it applies also to 19 | any other work released this way by its authors. You can apply it to 20 | your programs, too. 21 | 22 | When we speak of free software, we are referring to freedom, not 23 | price. Our General Public Licenses are designed to make sure that you 24 | have the freedom to distribute copies of free software (and charge for 25 | them if you wish), that you receive source code or can get it if you 26 | want it, that you can change the software or use pieces of it in new 27 | free programs, and that you know you can do these things. 28 | 29 | To protect your rights, we need to prevent others from denying you 30 | these rights or asking you to surrender the rights. Therefore, you have 31 | certain responsibilities if you distribute copies of the software, or if 32 | you modify it: responsibilities to respect the freedom of others. 33 | 34 | For example, if you distribute copies of such a program, whether 35 | gratis or for a fee, you must pass on to the recipients the same 36 | freedoms that you received. You must make sure that they, too, receive 37 | or can get the source code. And you must show them these terms so they 38 | know their rights. 39 | 40 | Developers that use the GNU GPL protect your rights with two steps: 41 | (1) assert copyright on the software, and (2) offer you this License 42 | giving you legal permission to copy, distribute and/or modify it. 43 | 44 | For the developers' and authors' protection, the GPL clearly explains 45 | that there is no warranty for this free software. For both users' and 46 | authors' sake, the GPL requires that modified versions be marked as 47 | changed, so that their problems will not be attributed erroneously to 48 | authors of previous versions. 49 | 50 | Some devices are designed to deny users access to install or run 51 | modified versions of the software inside them, although the manufacturer 52 | can do so. This is fundamentally incompatible with the aim of 53 | protecting users' freedom to change the software. The systematic 54 | pattern of such abuse occurs in the area of products for individuals to 55 | use, which is precisely where it is most unacceptable. Therefore, we 56 | have designed this version of the GPL to prohibit the practice for those 57 | products. If such problems arise substantially in other domains, we 58 | stand ready to extend this provision to those domains in future versions 59 | of the GPL, as needed to protect the freedom of users. 60 | 61 | Finally, every program is threatened constantly by software patents. 62 | States should not allow patents to restrict development and use of 63 | software on general-purpose computers, but in those that do, we wish to 64 | avoid the special danger that patents applied to a free program could 65 | make it effectively proprietary. To prevent this, the GPL assures that 66 | patents cannot be used to render the program non-free. 67 | 68 | The precise terms and conditions for copying, distribution and 69 | modification follow. 70 | 71 | TERMS AND CONDITIONS 72 | 73 | 0. Definitions. 74 | 75 | "This License" refers to version 3 of the GNU General Public License. 76 | 77 | "Copyright" also means copyright-like laws that apply to other kinds of 78 | works, such as semiconductor masks. 79 | 80 | "The Program" refers to any copyrightable work licensed under this 81 | License. Each licensee is addressed as "you". "Licensees" and 82 | "recipients" may be individuals or organizations. 83 | 84 | To "modify" a work means to copy from or adapt all or part of the work 85 | in a fashion requiring copyright permission, other than the making of an 86 | exact copy. The resulting work is called a "modified version" of the 87 | earlier work or a work "based on" the earlier work. 88 | 89 | A "covered work" means either the unmodified Program or a work based 90 | on the Program. 91 | 92 | To "propagate" a work means to do anything with it that, without 93 | permission, would make you directly or secondarily liable for 94 | infringement under applicable copyright law, except executing it on a 95 | computer or modifying a private copy. Propagation includes copying, 96 | distribution (with or without modification), making available to the 97 | public, and in some countries other activities as well. 98 | 99 | To "convey" a work means any kind of propagation that enables other 100 | parties to make or receive copies. Mere interaction with a user through 101 | a computer network, with no transfer of a copy, is not conveying. 102 | 103 | An interactive user interface displays "Appropriate Legal Notices" 104 | to the extent that it includes a convenient and prominently visible 105 | feature that (1) displays an appropriate copyright notice, and (2) 106 | tells the user that there is no warranty for the work (except to the 107 | extent that warranties are provided), that licensees may convey the 108 | work under this License, and how to view a copy of this License. If 109 | the interface presents a list of user commands or options, such as a 110 | menu, a prominent item in the list meets this criterion. 111 | 112 | 1. Source Code. 113 | 114 | The "source code" for a work means the preferred form of the work 115 | for making modifications to it. "Object code" means any non-source 116 | form of a work. 117 | 118 | A "Standard Interface" means an interface that either is an official 119 | standard defined by a recognized standards body, or, in the case of 120 | interfaces specified for a particular programming language, one that 121 | is widely used among developers working in that language. 122 | 123 | The "System Libraries" of an executable work include anything, other 124 | than the work as a whole, that (a) is included in the normal form of 125 | packaging a Major Component, but which is not part of that Major 126 | Component, and (b) serves only to enable use of the work with that 127 | Major Component, or to implement a Standard Interface for which an 128 | implementation is available to the public in source code form. A 129 | "Major Component", in this context, means a major essential component 130 | (kernel, window system, and so on) of the specific operating system 131 | (if any) on which the executable work runs, or a compiler used to 132 | produce the work, or an object code interpreter used to run it. 133 | 134 | The "Corresponding Source" for a work in object code form means all 135 | the source code needed to generate, install, and (for an executable 136 | work) run the object code and to modify the work, including scripts to 137 | control those activities. However, it does not include the work's 138 | System Libraries, or general-purpose tools or generally available free 139 | programs which are used unmodified in performing those activities but 140 | which are not part of the work. For example, Corresponding Source 141 | includes interface definition files associated with source files for 142 | the work, and the source code for shared libraries and dynamically 143 | linked subprograms that the work is specifically designed to require, 144 | such as by intimate data communication or control flow between those 145 | subprograms and other parts of the work. 146 | 147 | The Corresponding Source need not include anything that users 148 | can regenerate automatically from other parts of the Corresponding 149 | Source. 150 | 151 | The Corresponding Source for a work in source code form is that 152 | same work. 153 | 154 | 2. Basic Permissions. 155 | 156 | All rights granted under this License are granted for the term of 157 | copyright on the Program, and are irrevocable provided the stated 158 | conditions are met. This License explicitly affirms your unlimited 159 | permission to run the unmodified Program. The output from running a 160 | covered work is covered by this License only if the output, given its 161 | content, constitutes a covered work. This License acknowledges your 162 | rights of fair use or other equivalent, as provided by copyright law. 163 | 164 | You may make, run and propagate covered works that you do not 165 | convey, without conditions so long as your license otherwise remains 166 | in force. You may convey covered works to others for the sole purpose 167 | of having them make modifications exclusively for you, or provide you 168 | with facilities for running those works, provided that you comply with 169 | the terms of this License in conveying all material for which you do 170 | not control copyright. Those thus making or running the covered works 171 | for you must do so exclusively on your behalf, under your direction 172 | and control, on terms that prohibit them from making any copies of 173 | your copyrighted material outside their relationship with you. 174 | 175 | Conveying under any other circumstances is permitted solely under 176 | the conditions stated below. Sublicensing is not allowed; section 10 177 | makes it unnecessary. 178 | 179 | 3. Protecting Users' Legal Rights From Anti-Circumvention Law. 180 | 181 | No covered work shall be deemed part of an effective technological 182 | measure under any applicable law fulfilling obligations under article 183 | 11 of the WIPO copyright treaty adopted on 20 December 1996, or 184 | similar laws prohibiting or restricting circumvention of such 185 | measures. 186 | 187 | When you convey a covered work, you waive any legal power to forbid 188 | circumvention of technological measures to the extent such circumvention 189 | is effected by exercising rights under this License with respect to 190 | the covered work, and you disclaim any intention to limit operation or 191 | modification of the work as a means of enforcing, against the work's 192 | users, your or third parties' legal rights to forbid circumvention of 193 | technological measures. 194 | 195 | 4. Conveying Verbatim Copies. 196 | 197 | You may convey verbatim copies of the Program's source code as you 198 | receive it, in any medium, provided that you conspicuously and 199 | appropriately publish on each copy an appropriate copyright notice; 200 | keep intact all notices stating that this License and any 201 | non-permissive terms added in accord with section 7 apply to the code; 202 | keep intact all notices of the absence of any warranty; and give all 203 | recipients a copy of this License along with the Program. 204 | 205 | You may charge any price or no price for each copy that you convey, 206 | and you may offer support or warranty protection for a fee. 207 | 208 | 5. Conveying Modified Source Versions. 209 | 210 | You may convey a work based on the Program, or the modifications to 211 | produce it from the Program, in the form of source code under the 212 | terms of section 4, provided that you also meet all of these conditions: 213 | 214 | a) The work must carry prominent notices stating that you modified 215 | it, and giving a relevant date. 216 | 217 | b) The work must carry prominent notices stating that it is 218 | released under this License and any conditions added under section 219 | 7. This requirement modifies the requirement in section 4 to 220 | "keep intact all notices". 221 | 222 | c) You must license the entire work, as a whole, under this 223 | License to anyone who comes into possession of a copy. This 224 | License will therefore apply, along with any applicable section 7 225 | additional terms, to the whole of the work, and all its parts, 226 | regardless of how they are packaged. This License gives no 227 | permission to license the work in any other way, but it does not 228 | invalidate such permission if you have separately received it. 229 | 230 | d) If the work has interactive user interfaces, each must display 231 | Appropriate Legal Notices; however, if the Program has interactive 232 | interfaces that do not display Appropriate Legal Notices, your 233 | work need not make them do so. 234 | 235 | A compilation of a covered work with other separate and independent 236 | works, which are not by their nature extensions of the covered work, 237 | and which are not combined with it such as to form a larger program, 238 | in or on a volume of a storage or distribution medium, is called an 239 | "aggregate" if the compilation and its resulting copyright are not 240 | used to limit the access or legal rights of the compilation's users 241 | beyond what the individual works permit. Inclusion of a covered work 242 | in an aggregate does not cause this License to apply to the other 243 | parts of the aggregate. 244 | 245 | 6. Conveying Non-Source Forms. 246 | 247 | You may convey a covered work in object code form under the terms 248 | of sections 4 and 5, provided that you also convey the 249 | machine-readable Corresponding Source under the terms of this License, 250 | in one of these ways: 251 | 252 | a) Convey the object code in, or embodied in, a physical product 253 | (including a physical distribution medium), accompanied by the 254 | Corresponding Source fixed on a durable physical medium 255 | customarily used for software interchange. 256 | 257 | b) Convey the object code in, or embodied in, a physical product 258 | (including a physical distribution medium), accompanied by a 259 | written offer, valid for at least three years and valid for as 260 | long as you offer spare parts or customer support for that product 261 | model, to give anyone who possesses the object code either (1) a 262 | copy of the Corresponding Source for all the software in the 263 | product that is covered by this License, on a durable physical 264 | medium customarily used for software interchange, for a price no 265 | more than your reasonable cost of physically performing this 266 | conveying of source, or (2) access to copy the 267 | Corresponding Source from a network server at no charge. 268 | 269 | c) Convey individual copies of the object code with a copy of the 270 | written offer to provide the Corresponding Source. This 271 | alternative is allowed only occasionally and noncommercially, and 272 | only if you received the object code with such an offer, in accord 273 | with subsection 6b. 274 | 275 | d) Convey the object code by offering access from a designated 276 | place (gratis or for a charge), and offer equivalent access to the 277 | Corresponding Source in the same way through the same place at no 278 | further charge. You need not require recipients to copy the 279 | Corresponding Source along with the object code. If the place to 280 | copy the object code is a network server, the Corresponding Source 281 | may be on a different server (operated by you or a third party) 282 | that supports equivalent copying facilities, provided you maintain 283 | clear directions next to the object code saying where to find the 284 | Corresponding Source. Regardless of what server hosts the 285 | Corresponding Source, you remain obligated to ensure that it is 286 | available for as long as needed to satisfy these requirements. 287 | 288 | e) Convey the object code using peer-to-peer transmission, provided 289 | you inform other peers where the object code and Corresponding 290 | Source of the work are being offered to the general public at no 291 | charge under subsection 6d. 292 | 293 | A separable portion of the object code, whose source code is excluded 294 | from the Corresponding Source as a System Library, need not be 295 | included in conveying the object code work. 296 | 297 | A "User Product" is either (1) a "consumer product", which means any 298 | tangible personal property which is normally used for personal, family, 299 | or household purposes, or (2) anything designed or sold for incorporation 300 | into a dwelling. In determining whether a product is a consumer product, 301 | doubtful cases shall be resolved in favor of coverage. For a particular 302 | product received by a particular user, "normally used" refers to a 303 | typical or common use of that class of product, regardless of the status 304 | of the particular user or of the way in which the particular user 305 | actually uses, or expects or is expected to use, the product. A product 306 | is a consumer product regardless of whether the product has substantial 307 | commercial, industrial or non-consumer uses, unless such uses represent 308 | the only significant mode of use of the product. 309 | 310 | "Installation Information" for a User Product means any methods, 311 | procedures, authorization keys, or other information required to install 312 | and execute modified versions of a covered work in that User Product from 313 | a modified version of its Corresponding Source. The information must 314 | suffice to ensure that the continued functioning of the modified object 315 | code is in no case prevented or interfered with solely because 316 | modification has been made. 317 | 318 | If you convey an object code work under this section in, or with, or 319 | specifically for use in, a User Product, and the conveying occurs as 320 | part of a transaction in which the right of possession and use of the 321 | User Product is transferred to the recipient in perpetuity or for a 322 | fixed term (regardless of how the transaction is characterized), the 323 | Corresponding Source conveyed under this section must be accompanied 324 | by the Installation Information. But this requirement does not apply 325 | if neither you nor any third party retains the ability to install 326 | modified object code on the User Product (for example, the work has 327 | been installed in ROM). 328 | 329 | The requirement to provide Installation Information does not include a 330 | requirement to continue to provide support service, warranty, or updates 331 | for a work that has been modified or installed by the recipient, or for 332 | the User Product in which it has been modified or installed. Access to a 333 | network may be denied when the modification itself materially and 334 | adversely affects the operation of the network or violates the rules and 335 | protocols for communication across the network. 336 | 337 | Corresponding Source conveyed, and Installation Information provided, 338 | in accord with this section must be in a format that is publicly 339 | documented (and with an implementation available to the public in 340 | source code form), and must require no special password or key for 341 | unpacking, reading or copying. 342 | 343 | 7. Additional Terms. 344 | 345 | "Additional permissions" are terms that supplement the terms of this 346 | License by making exceptions from one or more of its conditions. 347 | Additional permissions that are applicable to the entire Program shall 348 | be treated as though they were included in this License, to the extent 349 | that they are valid under applicable law. If additional permissions 350 | apply only to part of the Program, that part may be used separately 351 | under those permissions, but the entire Program remains governed by 352 | this License without regard to the additional permissions. 353 | 354 | When you convey a copy of a covered work, you may at your option 355 | remove any additional permissions from that copy, or from any part of 356 | it. (Additional permissions may be written to require their own 357 | removal in certain cases when you modify the work.) You may place 358 | additional permissions on material, added by you to a covered work, 359 | for which you have or can give appropriate copyright permission. 360 | 361 | Notwithstanding any other provision of this License, for material you 362 | add to a covered work, you may (if authorized by the copyright holders of 363 | that material) supplement the terms of this License with terms: 364 | 365 | a) Disclaiming warranty or limiting liability differently from the 366 | terms of sections 15 and 16 of this License; or 367 | 368 | b) Requiring preservation of specified reasonable legal notices or 369 | author attributions in that material or in the Appropriate Legal 370 | Notices displayed by works containing it; or 371 | 372 | c) Prohibiting misrepresentation of the origin of that material, or 373 | requiring that modified versions of such material be marked in 374 | reasonable ways as different from the original version; or 375 | 376 | d) Limiting the use for publicity purposes of names of licensors or 377 | authors of the material; or 378 | 379 | e) Declining to grant rights under trademark law for use of some 380 | trade names, trademarks, or service marks; or 381 | 382 | f) Requiring indemnification of licensors and authors of that 383 | material by anyone who conveys the material (or modified versions of 384 | it) with contractual assumptions of liability to the recipient, for 385 | any liability that these contractual assumptions directly impose on 386 | those licensors and authors. 387 | 388 | All other non-permissive additional terms are considered "further 389 | restrictions" within the meaning of section 10. If the Program as you 390 | received it, or any part of it, contains a notice stating that it is 391 | governed by this License along with a term that is a further 392 | restriction, you may remove that term. If a license document contains 393 | a further restriction but permits relicensing or conveying under this 394 | License, you may add to a covered work material governed by the terms 395 | of that license document, provided that the further restriction does 396 | not survive such relicensing or conveying. 397 | 398 | If you add terms to a covered work in accord with this section, you 399 | must place, in the relevant source files, a statement of the 400 | additional terms that apply to those files, or a notice indicating 401 | where to find the applicable terms. 402 | 403 | Additional terms, permissive or non-permissive, may be stated in the 404 | form of a separately written license, or stated as exceptions; 405 | the above requirements apply either way. 406 | 407 | 8. Termination. 408 | 409 | You may not propagate or modify a covered work except as expressly 410 | provided under this License. Any attempt otherwise to propagate or 411 | modify it is void, and will automatically terminate your rights under 412 | this License (including any patent licenses granted under the third 413 | paragraph of section 11). 414 | 415 | However, if you cease all violation of this License, then your 416 | license from a particular copyright holder is reinstated (a) 417 | provisionally, unless and until the copyright holder explicitly and 418 | finally terminates your license, and (b) permanently, if the copyright 419 | holder fails to notify you of the violation by some reasonable means 420 | prior to 60 days after the cessation. 421 | 422 | Moreover, your license from a particular copyright holder is 423 | reinstated permanently if the copyright holder notifies you of the 424 | violation by some reasonable means, this is the first time you have 425 | received notice of violation of this License (for any work) from that 426 | copyright holder, and you cure the violation prior to 30 days after 427 | your receipt of the notice. 428 | 429 | Termination of your rights under this section does not terminate the 430 | licenses of parties who have received copies or rights from you under 431 | this License. If your rights have been terminated and not permanently 432 | reinstated, you do not qualify to receive new licenses for the same 433 | material under section 10. 434 | 435 | 9. Acceptance Not Required for Having Copies. 436 | 437 | You are not required to accept this License in order to receive or 438 | run a copy of the Program. Ancillary propagation of a covered work 439 | occurring solely as a consequence of using peer-to-peer transmission 440 | to receive a copy likewise does not require acceptance. However, 441 | nothing other than this License grants you permission to propagate or 442 | modify any covered work. These actions infringe copyright if you do 443 | not accept this License. Therefore, by modifying or propagating a 444 | covered work, you indicate your acceptance of this License to do so. 445 | 446 | 10. Automatic Licensing of Downstream Recipients. 447 | 448 | Each time you convey a covered work, the recipient automatically 449 | receives a license from the original licensors, to run, modify and 450 | propagate that work, subject to this License. You are not responsible 451 | for enforcing compliance by third parties with this License. 452 | 453 | An "entity transaction" is a transaction transferring control of an 454 | organization, or substantially all assets of one, or subdividing an 455 | organization, or merging organizations. If propagation of a covered 456 | work results from an entity transaction, each party to that 457 | transaction who receives a copy of the work also receives whatever 458 | licenses to the work the party's predecessor in interest had or could 459 | give under the previous paragraph, plus a right to possession of the 460 | Corresponding Source of the work from the predecessor in interest, if 461 | the predecessor has it or can get it with reasonable efforts. 462 | 463 | You may not impose any further restrictions on the exercise of the 464 | rights granted or affirmed under this License. For example, you may 465 | not impose a license fee, royalty, or other charge for exercise of 466 | rights granted under this License, and you may not initiate litigation 467 | (including a cross-claim or counterclaim in a lawsuit) alleging that 468 | any patent claim is infringed by making, using, selling, offering for 469 | sale, or importing the Program or any portion of it. 470 | 471 | 11. Patents. 472 | 473 | A "contributor" is a copyright holder who authorizes use under this 474 | License of the Program or a work on which the Program is based. The 475 | work thus licensed is called the contributor's "contributor version". 476 | 477 | A contributor's "essential patent claims" are all patent claims 478 | owned or controlled by the contributor, whether already acquired or 479 | hereafter acquired, that would be infringed by some manner, permitted 480 | by this License, of making, using, or selling its contributor version, 481 | but do not include claims that would be infringed only as a 482 | consequence of further modification of the contributor version. For 483 | purposes of this definition, "control" includes the right to grant 484 | patent sublicenses in a manner consistent with the requirements of 485 | this License. 486 | 487 | Each contributor grants you a non-exclusive, worldwide, royalty-free 488 | patent license under the contributor's essential patent claims, to 489 | make, use, sell, offer for sale, import and otherwise run, modify and 490 | propagate the contents of its contributor version. 491 | 492 | In the following three paragraphs, a "patent license" is any express 493 | agreement or commitment, however denominated, not to enforce a patent 494 | (such as an express permission to practice a patent or covenant not to 495 | sue for patent infringement). To "grant" such a patent license to a 496 | party means to make such an agreement or commitment not to enforce a 497 | patent against the party. 498 | 499 | If you convey a covered work, knowingly relying on a patent license, 500 | and the Corresponding Source of the work is not available for anyone 501 | to copy, free of charge and under the terms of this License, through a 502 | publicly available network server or other readily accessible means, 503 | then you must either (1) cause the Corresponding Source to be so 504 | available, or (2) arrange to deprive yourself of the benefit of the 505 | patent license for this particular work, or (3) arrange, in a manner 506 | consistent with the requirements of this License, to extend the patent 507 | license to downstream recipients. "Knowingly relying" means you have 508 | actual knowledge that, but for the patent license, your conveying the 509 | covered work in a country, or your recipient's use of the covered work 510 | in a country, would infringe one or more identifiable patents in that 511 | country that you have reason to believe are valid. 512 | 513 | If, pursuant to or in connection with a single transaction or 514 | arrangement, you convey, or propagate by procuring conveyance of, a 515 | covered work, and grant a patent license to some of the parties 516 | receiving the covered work authorizing them to use, propagate, modify 517 | or convey a specific copy of the covered work, then the patent license 518 | you grant is automatically extended to all recipients of the covered 519 | work and works based on it. 520 | 521 | A patent license is "discriminatory" if it does not include within 522 | the scope of its coverage, prohibits the exercise of, or is 523 | conditioned on the non-exercise of one or more of the rights that are 524 | specifically granted under this License. You may not convey a covered 525 | work if you are a party to an arrangement with a third party that is 526 | in the business of distributing software, under which you make payment 527 | to the third party based on the extent of your activity of conveying 528 | the work, and under which the third party grants, to any of the 529 | parties who would receive the covered work from you, a discriminatory 530 | patent license (a) in connection with copies of the covered work 531 | conveyed by you (or copies made from those copies), or (b) primarily 532 | for and in connection with specific products or compilations that 533 | contain the covered work, unless you entered into that arrangement, 534 | or that patent license was granted, prior to 28 March 2007. 535 | 536 | Nothing in this License shall be construed as excluding or limiting 537 | any implied license or other defenses to infringement that may 538 | otherwise be available to you under applicable patent law. 539 | 540 | 12. No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | -------------------------------------------------------------------------------- /Makefile.am: -------------------------------------------------------------------------------- 1 | SUBDIRS = src 2 | EXTRA_DIST = autogen.sh LICENSE.txt README.md 3 | ACLOCAL_AMFLAGS = -I m4 4 | 5 | clean-local: 6 | rm -f core.* pystack 7 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Pystack 2 | 3 | Pystack is a program that can print the current stack trace for an arbitrary 4 | running Python process. It is a little like Python's 5 | [`traceback.print_tb()`](https://docs.python.org/2/library/traceback.html#traceback.print_tb), 6 | but rather than being a Python function it is a CLI tool that you can run 7 | against arbitrary processes that weren't already instrumented to dump their 8 | stack. There's a 9 | [blog post explaining how it works](https://eklitzke.org/pystack). 10 | 11 | You use it like this: 12 | 13 | pystack 14 | 15 | If everything goes correctly, you'll see the stack trace printed to stdout: 16 | 17 | $ pystack 15776 18 | ./blog/env/bin/blog-generate:9 19 | ./blog/blog/app.py:27 20 | ./blog/blog/generate.py:53 21 | ./blog/blog/generate.py:61 22 | ./blog/blog/parser.py:101 23 | ./blog/env/lib/python2.7/site-packages/markdown/__init__.py:371 24 | ./blog/env/lib/python2.7/site-packages/markdown/blockparser.py:65 25 | ./blog/env/lib/python2.7/site-packages/markdown/blockparser.py:80 26 | ./blog/env/lib/python2.7/site-packages/markdown/blockparser.py:97 27 | ./blog/env/lib/python2.7/site-packages/markdown/blockprocessors.py:429 28 | 29 | The output is ordered according to the same convention as a Python "backtrace", 30 | i.e. such that the most recently executed line is on the bottom of the output 31 | and the least recently executed line is on the top of the output. 32 | 33 | Pystack is implemented using the magic of the 34 | [`ptrace(2)`](http://man7.org/linux/man-pages/man2/ptrace.2.html) system call. 35 | Conceptually it works in a similar way to GDB. Pystack will attach to an 36 | arbitrary PID and then use the magic of ptrace to peer into the Python 37 | interpreter's memory and extract the current stack trace. See the "How Does It 38 | Work?" section below for more details. 39 | 40 | I wrote this software because I was frustrated with the existing profiling and 41 | debugging tools available for Python. I believe that this kind of software can 42 | be useful as the basis of high quality, low overhead profiling tools. See 43 | "Advanced Usage" below. 44 | 45 | ## What Platforms Does It Work On? 46 | 47 | Currently Pystack only works on 64-bit Linux systems. It should be relatively 48 | easy to port to 32-bit systems and BSD. 49 | 50 | In principle it can be made to work on OS X. The hardest part would be extracing 51 | symbols out of the Python binary, as OS X uses the Mach-O executable format 52 | rather than ELF. If you have a non-hacky way to extract symbols on OS X send me 53 | a pull request. 54 | 55 | Generally there are two ways to compile the Python interpreter. In the default 56 | compilation mode you get a "static" binary that has the Python symbols built in. 57 | If instead Python was compiled with the `--enable-shared` option you get a 58 | "dynamic" binary that links against libpython, and libpython has the actual 59 | interpreter symbols. The "static" mode is the default and what is also shipped 60 | by most Linux distributions. The "dynamic" mode is used by Fedora (and possibly 61 | other distributions). Pystack can detect how the Python interpreter was built 62 | and supports both use cases. You can also use Pystack with processes that embed 63 | Python, e.g. [uWSGI](https://uwsgi-docs.readthedocs.io/en/latest/). 64 | 65 | ## Compiling 66 | 67 | You'll need the following: 68 | 69 | * A C++ compiler with C++11 support 70 | * Autotools (autoconf + automake) 71 | * Python headers 72 | 73 | Then in the root of the project run: 74 | 75 | ./autogen.sh 76 | 77 | This will create the `./configure` file. You can then proceed with the build as 78 | usual: 79 | 80 | ./configure 81 | make 82 | make install 83 | 84 | This invocation should install the correct build dependencies on Fedora: 85 | 86 | sudo dnf install autoconf automake gcc-c++ python-devel 87 | 88 | This invocation should install the correct build dependencies on Debian/Ubuntu: 89 | 90 | sudo apt-get install autoconf build-essential pkg-config python-dev 91 | 92 | ### I'm Young and Hip and Want To Use Python 3 93 | 94 | That's supported! Compile Pystack like this: 95 | 96 | ./configure --with-python=python3 97 | 98 | If you have file names that contain non-ASCII Unicode code points you may get 99 | incorrect output. Pull requests to improve Unicode handling here are very 100 | welcome. 101 | 102 | ## How Does It Work? 103 | 104 | As already mentioned, Pystack uses the `ptrace(2)` system call to read a remote 105 | process's memory image. It works roughly like this: 106 | 107 | * attach to the process using `PTRACE_ATTACH` 108 | * read and decode the ELF executable for the process 109 | * based on what is read from the ELF, determine if this is a static or dynamic 110 | Python build 111 | * locate the `_PyThreadState_Current` symbol (which will either be in the 112 | Python interpreter, or in libpython, depending on the interpreter build mode) 113 | * if the symbol exists in libpython, find the 114 | [ASLR](https://en.wikipedia.org/wiki/Address_space_layout_randomization) 115 | offset for libpython 116 | * locate the current frame object from `_PyThreadState_Current` and then 117 | recursively use the `PTRACE_PEEKDATA` command to read stack frames and decode 118 | their fields 119 | 120 | Everything but the last step is setup work. Therefore Pystack implements a 121 | mechanism to "monitor" a process and get repeated dumps. In the monitoring mode 122 | the setup work is done only once, and then Pystack repeatedly attaches and dumps 123 | the process at a given frequency. When monitoring a process in such a way the 124 | process can be queried at a very high sample rate, which is useful for 125 | profiling. You use the monitoring mode like this: 126 | 127 | pystack -s 5 -r 0.001 4282 128 | 129 | This would sample PID 4282 for 5 seconds waiting 1 millisecond (i.e. 0.001 130 | seconds) between each sample. 131 | 132 | ## Advanced Usage 133 | 134 | You can use Pystack to build a Python profiler of your design. It's fun and 135 | easy! 136 | 137 | Normal Python profilers like 138 | [profile and cProfile](https://docs.python.org/2/library/profile.html) work by 139 | using the 140 | [`sys.settrace()`](https://docs.python.org/2/library/sys.html#sys.settrace) 141 | routine. This lets you register a callback that the Python interpreter runs very 142 | frequently. This is nice because the profiling function is run very often and at 143 | all of the interesting points in your program which yields good data. However 144 | this approach also has very high overhead. 145 | 146 | You can also build a high-resolution signal based timer using 147 | [`signal.setitimer()`](https://docs.python.org/2/library/signal.html#signal.setitimer), 148 | and this is what a number of Python projects actually do. However, you need to 149 | have your process already instrumented to do this, and the overhead can be high 150 | if the signal handler is also Python code. 151 | 152 | Pystack has the following nice properties 153 | 154 | * you can run it on any process, without having planned to use it beforehand 155 | * you can run it any granularity you find useful, whether that's very fast 156 | (e.g. microsecond granulariy) or very slow (e.g. second granularity) 157 | * it's implemented in C++ with an eye for efficiency, so it's very fast and the 158 | pause times are low 159 | 160 | The monitoring mode is described in the previous section ("How Does It Work?"). 161 | There's a tradeoff to be made here between sampling frequency and overhead: 162 | higher sampling rates will get more accurate data, but at the cost of higher 163 | overhead. Building a profiler based on Pystack is left as an exercise to the 164 | reader. 165 | 166 | ## Troubleshooting 167 | 168 | This section explains some of the more common error messages you might see. 169 | 170 | ### "No active frame for the Python interpreter." 171 | 172 | You may see this error message from time to time. What does it mean? 173 | 174 | Interestingly the Python interpreter does not always have an active frame. For 175 | instance, if you take an idle Python REPL and attach it with GDB, you'll get a 176 | stack trace somewhat like this: 177 | 178 | (gdb) bt 179 | #0 0x00007ff1d8a3c0e3 in __select_nocancel () at ../sysdeps/unix/syscall-template.S:84 180 | #1 0x00007ff1d1bc6908 in call_readline () from /usr/lib64/python2.7/lib-dynload/readline.so 181 | #2 0x00007ff1d9675200 in PyOS_Readline () from /lib64/libpython2.7.so.1.0 182 | #3 0x00007ff1d9675ed7 in tok_nextc () from /lib64/libpython2.7.so.1.0 183 | #4 0x00007ff1d9676d28 in PyTokenizer_Get () from /lib64/libpython2.7.so.1.0 184 | #5 0x00007ff1d9672b0f in parsetok () from /lib64/libpython2.7.so.1.0 185 | #6 0x00007ff1d9732162 in PyParser_ASTFromFile () from /lib64/libpython2.7.so.1.0 186 | #7 0x00007ff1d97330ca in PyRun_InteractiveOneFlags () from /lib64/libpython2.7.so.1.0 187 | #8 0x00007ff1d973330e in PyRun_InteractiveLoopFlags () from /lib64/libpython2.7.so.1.0 188 | #9 0x00007ff1d973398e in PyRun_AnyFileExFlags () from /lib64/libpython2.7.so.1.0 189 | #10 0x00007ff1d97454a0 in Py_Main () from /lib64/libpython2.7.so.1.0 190 | #11 0x00007ff1d8963731 in __libc_start_main (main=0x558ff2f927b0
, argc=1, argv=0x7ffd709e7a08, init=, 191 | fini=, rtld_fini=, stack_end=0x7ffd709e79f8) at ../csu/libc-start.c:289 192 | #12 0x0000558ff2f927e9 in _start () 193 | 194 | None of the functions in this backtrace are evaluating a frame object. By 195 | contrast, if you look at the stack trace for a Python process doing real work 196 | you'll typically see `PyEval_EvalFrameEx` somewhere in the stack trace, which is 197 | the function that typically evaluates a Python frame object. In this situation 198 | the tail-most instance of `PyEval_EvalFrameEx` will be evaluating the "current" 199 | frame. 200 | 201 | Concretely, we say there is no active frame when `_PyThreadState_Current` is a 202 | null pointer. 203 | 204 | One simple way to reproduce this issue is to put a line of code like this in a 205 | Python file you are tracing: 206 | 207 | ```python 208 | import select 209 | select.select([], [], []) 210 | ``` 211 | 212 | This will cause the Python process to hang forever, but `_PyThreadState_Current` 213 | will be a null pointer and thus there will be no active frame. 214 | 215 | This also arises in embedding contexts. If you look at a uWSGI process that is 216 | currently serving a request it will have an active frame, but a uWSGI process 217 | that is just idle and waiting for traffic will not have an active frame. 218 | 219 | ### Failed to PTRACE_PEEKDATA at 0x2b: Input/output error 220 | 221 | If you consistently get an error like this the most likely explanation is that 222 | you built against Python 2 but are trying to trace a Python 3 program (or vice 223 | versa). The structure offsets for Python 2 and Python 3 are different, so if you 224 | have a mismatched build Pystack will get confused. 225 | 226 | To build against Python 2: 227 | 228 | ./configure 229 | 230 | To build against Python 3: 231 | 232 | ./configure --python=python3 233 | 234 | **TODO:** be better at auto-detecting the appropriate Python to build against, 235 | and also warn when the target appears to be mismatched. 236 | -------------------------------------------------------------------------------- /autogen.sh: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | autoreconf --install 3 | -------------------------------------------------------------------------------- /configure.ac: -------------------------------------------------------------------------------- 1 | AC_PREREQ([2.69]) 2 | AC_INIT([pystack], [1.0], [evan@eklitzke.org]) 3 | AC_CONFIG_AUX_DIR([build-aux]) 4 | AC_CONFIG_HEADERS([src/config.h]) 5 | AC_CONFIG_MACRO_DIR([m4]) 6 | AC_CONFIG_SRCDIR([src/pystack.cc]) 7 | 8 | AM_INIT_AUTOMAKE([dist-bzip2 foreign subdir-objects -Wall -Werror]) 9 | 10 | # Checks for programs. 11 | AC_PROG_CXX 12 | AC_PROG_CC 13 | AC_PROG_INSTALL 14 | 15 | AX_CXX_COMPILE_STDCXX_11 16 | 17 | # Checks for libraries. 18 | 19 | # Checks for header files. 20 | 21 | # Checks for typedefs, structures, and compiler characteristics. 22 | AC_CHECK_HEADER_STDBOOL 23 | 24 | # Checks for library functions. 25 | 26 | AC_ARG_WITH([python], 27 | [AS_HELP_STRING([--with-python], [specify python or python3 @<:@default=python@:>@])], 28 | [], 29 | [with_python="python"]) 30 | 31 | PKG_CHECK_MODULES([PYTHON], ["$with_python"]) 32 | AC_SUBST([PYTHON]) 33 | 34 | AC_CONFIG_FILES([Makefile 35 | src/Makefile]) 36 | AC_REVISION([m4_esyscmd_s([git describe --always])]) 37 | AC_OUTPUT 38 | -------------------------------------------------------------------------------- /m4/ax_cxx_compile_stdcxx.m4: -------------------------------------------------------------------------------- 1 | # =========================================================================== 2 | # http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html 3 | # =========================================================================== 4 | # 5 | # SYNOPSIS 6 | # 7 | # AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional]) 8 | # 9 | # DESCRIPTION 10 | # 11 | # Check for baseline language coverage in the compiler for the specified 12 | # version of the C++ standard. If necessary, add switches to CXX and 13 | # CXXCPP to enable support. VERSION may be '11' (for the C++11 standard) 14 | # or '14' (for the C++14 standard). 15 | # 16 | # The second argument, if specified, indicates whether you insist on an 17 | # extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. 18 | # -std=c++11). If neither is specified, you get whatever works, with 19 | # preference for an extended mode. 20 | # 21 | # The third argument, if specified 'mandatory' or if left unspecified, 22 | # indicates that baseline support for the specified C++ standard is 23 | # required and that the macro should error out if no mode with that 24 | # support is found. If specified 'optional', then configuration proceeds 25 | # regardless, after defining HAVE_CXX${VERSION} if and only if a 26 | # supporting mode is found. 27 | # 28 | # LICENSE 29 | # 30 | # Copyright (c) 2008 Benjamin Kosnik 31 | # Copyright (c) 2012 Zack Weinberg 32 | # Copyright (c) 2013 Roy Stogner 33 | # Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov 34 | # Copyright (c) 2015 Paul Norman 35 | # Copyright (c) 2015 Moritz Klammler 36 | # 37 | # Copying and distribution of this file, with or without modification, are 38 | # permitted in any medium without royalty provided the copyright notice 39 | # and this notice are preserved. This file is offered as-is, without any 40 | # warranty. 41 | 42 | #serial 4 43 | 44 | dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro 45 | dnl (serial version number 13). 46 | 47 | AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl 48 | m4_if([$1], [11], [], 49 | [$1], [14], [], 50 | [$1], [17], [m4_fatal([support for C++17 not yet implemented in AX_CXX_COMPILE_STDCXX])], 51 | [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl 52 | m4_if([$2], [], [], 53 | [$2], [ext], [], 54 | [$2], [noext], [], 55 | [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl 56 | m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true], 57 | [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true], 58 | [$3], [optional], [ax_cxx_compile_cxx$1_required=false], 59 | [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])]) 60 | AC_LANG_PUSH([C++])dnl 61 | ac_success=no 62 | AC_CACHE_CHECK(whether $CXX supports C++$1 features by default, 63 | ax_cv_cxx_compile_cxx$1, 64 | [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], 65 | [ax_cv_cxx_compile_cxx$1=yes], 66 | [ax_cv_cxx_compile_cxx$1=no])]) 67 | if test x$ax_cv_cxx_compile_cxx$1 = xyes; then 68 | ac_success=yes 69 | fi 70 | 71 | m4_if([$2], [noext], [], [dnl 72 | if test x$ac_success = xno; then 73 | for switch in -std=gnu++$1 -std=gnu++0x; do 74 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) 75 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, 76 | $cachevar, 77 | [ac_save_CXX="$CXX" 78 | CXX="$CXX $switch" 79 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], 80 | [eval $cachevar=yes], 81 | [eval $cachevar=no]) 82 | CXX="$ac_save_CXX"]) 83 | if eval test x\$$cachevar = xyes; then 84 | CXX="$CXX $switch" 85 | if test -n "$CXXCPP" ; then 86 | CXXCPP="$CXXCPP $switch" 87 | fi 88 | ac_success=yes 89 | break 90 | fi 91 | done 92 | fi]) 93 | 94 | m4_if([$2], [ext], [], [dnl 95 | if test x$ac_success = xno; then 96 | dnl HP's aCC needs +std=c++11 according to: 97 | dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf 98 | dnl Cray's crayCC needs "-h std=c++11" 99 | for switch in -std=c++$1 -std=c++0x +std=c++$1 "-h std=c++$1"; do 100 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) 101 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, 102 | $cachevar, 103 | [ac_save_CXX="$CXX" 104 | CXX="$CXX $switch" 105 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], 106 | [eval $cachevar=yes], 107 | [eval $cachevar=no]) 108 | CXX="$ac_save_CXX"]) 109 | if eval test x\$$cachevar = xyes; then 110 | CXX="$CXX $switch" 111 | if test -n "$CXXCPP" ; then 112 | CXXCPP="$CXXCPP $switch" 113 | fi 114 | ac_success=yes 115 | break 116 | fi 117 | done 118 | fi]) 119 | AC_LANG_POP([C++]) 120 | if test x$ax_cxx_compile_cxx$1_required = xtrue; then 121 | if test x$ac_success = xno; then 122 | AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.]) 123 | fi 124 | fi 125 | if test x$ac_success = xno; then 126 | HAVE_CXX$1=0 127 | AC_MSG_NOTICE([No compiler with C++$1 support was found]) 128 | else 129 | HAVE_CXX$1=1 130 | AC_DEFINE(HAVE_CXX$1,1, 131 | [define if the compiler supports basic C++$1 syntax]) 132 | fi 133 | AC_SUBST(HAVE_CXX$1) 134 | ]) 135 | 136 | 137 | dnl Test body for checking C++11 support 138 | 139 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11], 140 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 141 | ) 142 | 143 | 144 | dnl Test body for checking C++14 support 145 | 146 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14], 147 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 148 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 149 | ) 150 | 151 | 152 | dnl Tests for new features in C++11 153 | 154 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[ 155 | 156 | // If the compiler admits that it is not ready for C++11, why torture it? 157 | // Hopefully, this will speed up the test. 158 | 159 | #ifndef __cplusplus 160 | 161 | #error "This is not a C++ compiler" 162 | 163 | #elif __cplusplus < 201103L 164 | 165 | #error "This is not a C++11 compiler" 166 | 167 | #else 168 | 169 | namespace cxx11 170 | { 171 | 172 | namespace test_static_assert 173 | { 174 | 175 | template 176 | struct check 177 | { 178 | static_assert(sizeof(int) <= sizeof(T), "not big enough"); 179 | }; 180 | 181 | } 182 | 183 | namespace test_final_override 184 | { 185 | 186 | struct Base 187 | { 188 | virtual void f() {} 189 | }; 190 | 191 | struct Derived : public Base 192 | { 193 | virtual void f() override {} 194 | }; 195 | 196 | } 197 | 198 | namespace test_double_right_angle_brackets 199 | { 200 | 201 | template < typename T > 202 | struct check {}; 203 | 204 | typedef check single_type; 205 | typedef check> double_type; 206 | typedef check>> triple_type; 207 | typedef check>>> quadruple_type; 208 | 209 | } 210 | 211 | namespace test_decltype 212 | { 213 | 214 | int 215 | f() 216 | { 217 | int a = 1; 218 | decltype(a) b = 2; 219 | return a + b; 220 | } 221 | 222 | } 223 | 224 | namespace test_type_deduction 225 | { 226 | 227 | template < typename T1, typename T2 > 228 | struct is_same 229 | { 230 | static const bool value = false; 231 | }; 232 | 233 | template < typename T > 234 | struct is_same 235 | { 236 | static const bool value = true; 237 | }; 238 | 239 | template < typename T1, typename T2 > 240 | auto 241 | add(T1 a1, T2 a2) -> decltype(a1 + a2) 242 | { 243 | return a1 + a2; 244 | } 245 | 246 | int 247 | test(const int c, volatile int v) 248 | { 249 | static_assert(is_same::value == true, ""); 250 | static_assert(is_same::value == false, ""); 251 | static_assert(is_same::value == false, ""); 252 | auto ac = c; 253 | auto av = v; 254 | auto sumi = ac + av + 'x'; 255 | auto sumf = ac + av + 1.0; 256 | static_assert(is_same::value == true, ""); 257 | static_assert(is_same::value == true, ""); 258 | static_assert(is_same::value == true, ""); 259 | static_assert(is_same::value == false, ""); 260 | static_assert(is_same::value == true, ""); 261 | return (sumf > 0.0) ? sumi : add(c, v); 262 | } 263 | 264 | } 265 | 266 | namespace test_noexcept 267 | { 268 | 269 | int f() { return 0; } 270 | int g() noexcept { return 0; } 271 | 272 | static_assert(noexcept(f()) == false, ""); 273 | static_assert(noexcept(g()) == true, ""); 274 | 275 | } 276 | 277 | namespace test_constexpr 278 | { 279 | 280 | template < typename CharT > 281 | unsigned long constexpr 282 | strlen_c_r(const CharT *const s, const unsigned long acc) noexcept 283 | { 284 | return *s ? strlen_c_r(s + 1, acc + 1) : acc; 285 | } 286 | 287 | template < typename CharT > 288 | unsigned long constexpr 289 | strlen_c(const CharT *const s) noexcept 290 | { 291 | return strlen_c_r(s, 0UL); 292 | } 293 | 294 | static_assert(strlen_c("") == 0UL, ""); 295 | static_assert(strlen_c("1") == 1UL, ""); 296 | static_assert(strlen_c("example") == 7UL, ""); 297 | static_assert(strlen_c("another\0example") == 7UL, ""); 298 | 299 | } 300 | 301 | namespace test_rvalue_references 302 | { 303 | 304 | template < int N > 305 | struct answer 306 | { 307 | static constexpr int value = N; 308 | }; 309 | 310 | answer<1> f(int&) { return answer<1>(); } 311 | answer<2> f(const int&) { return answer<2>(); } 312 | answer<3> f(int&&) { return answer<3>(); } 313 | 314 | void 315 | test() 316 | { 317 | int i = 0; 318 | const int c = 0; 319 | static_assert(decltype(f(i))::value == 1, ""); 320 | static_assert(decltype(f(c))::value == 2, ""); 321 | static_assert(decltype(f(0))::value == 3, ""); 322 | } 323 | 324 | } 325 | 326 | namespace test_uniform_initialization 327 | { 328 | 329 | struct test 330 | { 331 | static const int zero {}; 332 | static const int one {1}; 333 | }; 334 | 335 | static_assert(test::zero == 0, ""); 336 | static_assert(test::one == 1, ""); 337 | 338 | } 339 | 340 | namespace test_lambdas 341 | { 342 | 343 | void 344 | test1() 345 | { 346 | auto lambda1 = [](){}; 347 | auto lambda2 = lambda1; 348 | lambda1(); 349 | lambda2(); 350 | } 351 | 352 | int 353 | test2() 354 | { 355 | auto a = [](int i, int j){ return i + j; }(1, 2); 356 | auto b = []() -> int { return '0'; }(); 357 | auto c = [=](){ return a + b; }(); 358 | auto d = [&](){ return c; }(); 359 | auto e = [a, &b](int x) mutable { 360 | const auto identity = [](int y){ return y; }; 361 | for (auto i = 0; i < a; ++i) 362 | a += b--; 363 | return x + identity(a + b); 364 | }(0); 365 | return a + b + c + d + e; 366 | } 367 | 368 | int 369 | test3() 370 | { 371 | const auto nullary = [](){ return 0; }; 372 | const auto unary = [](int x){ return x; }; 373 | using nullary_t = decltype(nullary); 374 | using unary_t = decltype(unary); 375 | const auto higher1st = [](nullary_t f){ return f(); }; 376 | const auto higher2nd = [unary](nullary_t f1){ 377 | return [unary, f1](unary_t f2){ return f2(unary(f1())); }; 378 | }; 379 | return higher1st(nullary) + higher2nd(nullary)(unary); 380 | } 381 | 382 | } 383 | 384 | namespace test_variadic_templates 385 | { 386 | 387 | template 388 | struct sum; 389 | 390 | template 391 | struct sum 392 | { 393 | static constexpr auto value = N0 + sum::value; 394 | }; 395 | 396 | template <> 397 | struct sum<> 398 | { 399 | static constexpr auto value = 0; 400 | }; 401 | 402 | static_assert(sum<>::value == 0, ""); 403 | static_assert(sum<1>::value == 1, ""); 404 | static_assert(sum<23>::value == 23, ""); 405 | static_assert(sum<1, 2>::value == 3, ""); 406 | static_assert(sum<5, 5, 11>::value == 21, ""); 407 | static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, ""); 408 | 409 | } 410 | 411 | // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae 412 | // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function 413 | // because of this. 414 | namespace test_template_alias_sfinae 415 | { 416 | 417 | struct foo {}; 418 | 419 | template 420 | using member = typename T::member_type; 421 | 422 | template 423 | void func(...) {} 424 | 425 | template 426 | void func(member*) {} 427 | 428 | void test(); 429 | 430 | void test() { func(0); } 431 | 432 | } 433 | 434 | } // namespace cxx11 435 | 436 | #endif // __cplusplus >= 201103L 437 | 438 | ]]) 439 | 440 | 441 | dnl Tests for new features in C++14 442 | 443 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[ 444 | 445 | // If the compiler admits that it is not ready for C++14, why torture it? 446 | // Hopefully, this will speed up the test. 447 | 448 | #ifndef __cplusplus 449 | 450 | #error "This is not a C++ compiler" 451 | 452 | #elif __cplusplus < 201402L 453 | 454 | #error "This is not a C++14 compiler" 455 | 456 | #else 457 | 458 | namespace cxx14 459 | { 460 | 461 | namespace test_polymorphic_lambdas 462 | { 463 | 464 | int 465 | test() 466 | { 467 | const auto lambda = [](auto&&... args){ 468 | const auto istiny = [](auto x){ 469 | return (sizeof(x) == 1UL) ? 1 : 0; 470 | }; 471 | const int aretiny[] = { istiny(args)... }; 472 | return aretiny[0]; 473 | }; 474 | return lambda(1, 1L, 1.0f, '1'); 475 | } 476 | 477 | } 478 | 479 | namespace test_binary_literals 480 | { 481 | 482 | constexpr auto ivii = 0b0000000000101010; 483 | static_assert(ivii == 42, "wrong value"); 484 | 485 | } 486 | 487 | namespace test_generalized_constexpr 488 | { 489 | 490 | template < typename CharT > 491 | constexpr unsigned long 492 | strlen_c(const CharT *const s) noexcept 493 | { 494 | auto length = 0UL; 495 | for (auto p = s; *p; ++p) 496 | ++length; 497 | return length; 498 | } 499 | 500 | static_assert(strlen_c("") == 0UL, ""); 501 | static_assert(strlen_c("x") == 1UL, ""); 502 | static_assert(strlen_c("test") == 4UL, ""); 503 | static_assert(strlen_c("another\0test") == 7UL, ""); 504 | 505 | } 506 | 507 | namespace test_lambda_init_capture 508 | { 509 | 510 | int 511 | test() 512 | { 513 | auto x = 0; 514 | const auto lambda1 = [a = x](int b){ return a + b; }; 515 | const auto lambda2 = [a = lambda1(x)](){ return a; }; 516 | return lambda2(); 517 | } 518 | 519 | } 520 | 521 | namespace test_digit_seperators 522 | { 523 | 524 | constexpr auto ten_million = 100'000'000; 525 | static_assert(ten_million == 100000000, ""); 526 | 527 | } 528 | 529 | namespace test_return_type_deduction 530 | { 531 | 532 | auto f(int& x) { return x; } 533 | decltype(auto) g(int& x) { return x; } 534 | 535 | template < typename T1, typename T2 > 536 | struct is_same 537 | { 538 | static constexpr auto value = false; 539 | }; 540 | 541 | template < typename T > 542 | struct is_same 543 | { 544 | static constexpr auto value = true; 545 | }; 546 | 547 | int 548 | test() 549 | { 550 | auto x = 0; 551 | static_assert(is_same::value, ""); 552 | static_assert(is_same::value, ""); 553 | return x; 554 | } 555 | 556 | } 557 | 558 | } // namespace cxx14 559 | 560 | #endif // __cplusplus >= 201402L 561 | 562 | ]]) 563 | -------------------------------------------------------------------------------- /m4/ax_cxx_compile_stdcxx_11.m4: -------------------------------------------------------------------------------- 1 | # ============================================================================ 2 | # http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html 3 | # ============================================================================ 4 | # 5 | # SYNOPSIS 6 | # 7 | # AX_CXX_COMPILE_STDCXX_11([ext|noext], [mandatory|optional]) 8 | # 9 | # DESCRIPTION 10 | # 11 | # Check for baseline language coverage in the compiler for the C++11 12 | # standard; if necessary, add switches to CXX and CXXCPP to enable 13 | # support. 14 | # 15 | # This macro is a convenience alias for calling the AX_CXX_COMPILE_STDCXX 16 | # macro with the version set to C++11. The two optional arguments are 17 | # forwarded literally as the second and third argument respectively. 18 | # Please see the documentation for the AX_CXX_COMPILE_STDCXX macro for 19 | # more information. If you want to use this macro, you also need to 20 | # download the ax_cxx_compile_stdcxx.m4 file. 21 | # 22 | # LICENSE 23 | # 24 | # Copyright (c) 2008 Benjamin Kosnik 25 | # Copyright (c) 2012 Zack Weinberg 26 | # Copyright (c) 2013 Roy Stogner 27 | # Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov 28 | # Copyright (c) 2015 Paul Norman 29 | # Copyright (c) 2015 Moritz Klammler 30 | # 31 | # Copying and distribution of this file, with or without modification, are 32 | # permitted in any medium without royalty provided the copyright notice 33 | # and this notice are preserved. This file is offered as-is, without any 34 | # warranty. 35 | 36 | #serial 17 37 | 38 | AX_REQUIRE_DEFINED([AX_CXX_COMPILE_STDCXX]) 39 | AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [AX_CXX_COMPILE_STDCXX([11], [$1], [$2])]) 40 | -------------------------------------------------------------------------------- /src/Makefile.am: -------------------------------------------------------------------------------- 1 | bin_PROGRAMS = pystack 2 | pystack_SOURCES = aslr.cc ptrace.cc pyframe.cc pystack.cc pystring.cc symbol.cc 3 | pystack_CXXFLAGS = $(PYTHON_CFLAGS) 4 | -------------------------------------------------------------------------------- /src/aslr.cc: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #include "./aslr.h" 17 | #include "./exc.h" 18 | 19 | #include 20 | #include 21 | #include 22 | 23 | namespace pystack { 24 | // Find libpython2.7.so and its offset for an ASLR process 25 | size_t LocateLibPython(pid_t pid, const std::string &hint, std::string *path) { 26 | std::ostringstream ss; 27 | ss << "/proc/" << pid << "/maps"; 28 | std::ifstream fp(ss.str()); 29 | std::string line; 30 | std::string elf_path; 31 | while (std::getline(fp, line)) { 32 | if (line.find(hint) != std::string::npos && 33 | line.find(" r-xp ") != std::string::npos) { 34 | size_t pos = line.find('/'); 35 | if (pos == std::string::npos) { 36 | throw FatalException("Did not find libpython absolute path"); 37 | } 38 | *path = line.substr(pos); 39 | pos = line.find('-'); 40 | if (pos == std::string::npos) { 41 | throw FatalException("Did not find libpython virtual memory address"); 42 | } 43 | return std::strtol(line.substr(0, pos).c_str(), nullptr, 16); 44 | } 45 | } 46 | return 0; 47 | } 48 | } // namespace pystack 49 | -------------------------------------------------------------------------------- /src/aslr.h: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #pragma once 17 | 18 | #include 19 | 20 | #include 21 | 22 | namespace pystack { 23 | // Find libpython2.7.so and its offset for an ASLR process. 24 | size_t LocateLibPython(pid_t pid, const std::string &hint, std::string *path); 25 | } // namespace pystack 26 | -------------------------------------------------------------------------------- /src/exc.h: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #pragma once 17 | 18 | #include 19 | #include 20 | 21 | namespace pystack { 22 | class NonFatalException : public std::runtime_error { 23 | public: 24 | explicit NonFatalException(const std::string &what_arg) 25 | : std::runtime_error(what_arg) {} 26 | }; 27 | 28 | class FatalException : public std::runtime_error { 29 | public: 30 | explicit FatalException(const std::string &what_arg) 31 | : std::runtime_error(what_arg) {} 32 | }; 33 | } // namespace pystack 34 | -------------------------------------------------------------------------------- /src/ptrace.cc: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #include "./ptrace.h" 17 | 18 | #include 19 | #include 20 | #include 21 | #include 22 | 23 | #include 24 | #include 25 | 26 | #include "./exc.h" 27 | 28 | namespace pystack { 29 | void PtraceAttach(pid_t pid) { 30 | if (ptrace(PTRACE_ATTACH, pid, 0, 0)) { 31 | std::ostringstream ss; 32 | ss << "Failed to attach to PID " << pid << ": " << strerror(errno); 33 | throw FatalException(ss.str()); 34 | } 35 | if (wait(nullptr) == -1) { 36 | std::ostringstream ss; 37 | ss << "Failed to wait on PID " << pid << ": " << strerror(errno); 38 | throw FatalException(ss.str()); 39 | } 40 | } 41 | 42 | void PtraceDetach(pid_t pid) { 43 | if (ptrace(PTRACE_DETACH, pid, 0, 0)) { 44 | std::ostringstream ss; 45 | ss << "Failed to detach PID " << pid << ": " << strerror(errno); 46 | throw FatalException(ss.str()); 47 | } 48 | } 49 | 50 | long PtracePeek(pid_t pid, unsigned long addr) { 51 | errno = 0; 52 | const long data = ptrace(PTRACE_PEEKDATA, pid, addr, 0); 53 | if (data == -1 && errno != 0) { 54 | std::ostringstream ss; 55 | ss << "Failed to PTRACE_PEEKDATA at " << reinterpret_cast(addr) 56 | << ": " << strerror(errno); 57 | throw FatalException(ss.str()); 58 | } 59 | return data; 60 | } 61 | 62 | std::string PtracePeekString(pid_t pid, unsigned long addr) { 63 | std::ostringstream dump; 64 | unsigned long off = 0; 65 | while (true) { 66 | const long val = PtracePeek(pid, addr + off); 67 | 68 | // XXX: this can be micro-optimized, c.f. 69 | // https://graphics.stanford.edu/~seander/bithacks.html#ZeroInWord 70 | const std::string chunk(reinterpret_cast(&val), sizeof(val)); 71 | dump << chunk.c_str(); 72 | if (chunk.find_first_of('\0') != std::string::npos) { 73 | break; 74 | } 75 | off += sizeof(val); 76 | } 77 | return dump.str(); 78 | } 79 | 80 | std::unique_ptr PtracePeekBytes(pid_t pid, unsigned long addr, 81 | size_t nbytes) { 82 | // align the buffer to a word size 83 | if (nbytes % sizeof(long)) { 84 | nbytes = (nbytes / sizeof(long) + 1) * sizeof(long); 85 | } 86 | std::unique_ptr bytes(new uint8_t[nbytes]); 87 | 88 | size_t off = 0; 89 | while (off < nbytes) { 90 | const long val = PtracePeek(pid, addr + off); 91 | memmove(bytes.get() + off, &val, sizeof(val)); 92 | off += sizeof(val); 93 | } 94 | return std::move(bytes); 95 | } 96 | } // namespace pystack 97 | -------------------------------------------------------------------------------- /src/ptrace.h: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #pragma once 17 | 18 | #include 19 | #include 20 | 21 | #include 22 | #include 23 | 24 | namespace pystack { 25 | // attach to a process 26 | void PtraceAttach(pid_t pid); 27 | 28 | // detach a process 29 | void PtraceDetach(pid_t pid); 30 | 31 | // read the long word at an address 32 | long PtracePeek(pid_t pid, unsigned long addr); 33 | 34 | // peek a null-terminated string 35 | std::string PtracePeekString(pid_t pid, unsigned long addr); 36 | 37 | // peek some number of bytes 38 | std::unique_ptr PtracePeekBytes(pid_t pid, unsigned long addr, 39 | size_t nbytes); 40 | } // namespace pystack 41 | -------------------------------------------------------------------------------- /src/pyframe.cc: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #include "./pyframe.h" 17 | 18 | #include 19 | #include 20 | #include 21 | #include 22 | #include 23 | #include 24 | #include 25 | 26 | // only needed for the struct offsets 27 | #include 28 | #include 29 | 30 | #include "./aslr.h" 31 | #include "./exc.h" 32 | #include "./ptrace.h" 33 | #include "./pystring.h" 34 | #include "./symbol.h" 35 | 36 | // why would this not be true idk 37 | static_assert(sizeof(long) == sizeof(void *), "wat platform r u on"); 38 | 39 | namespace pystack { 40 | namespace { 41 | // Extract the line number from the code object. Python uses a compressed table 42 | // data structure to store line numbers. See: 43 | // 44 | // https://svn.python.org/projects/python/trunk/Objects/lnotab_notes.txt 45 | // 46 | // This is essentially an implementation of PyFrame_GetLineNumber / 47 | // PyCode_Addr2Line. 48 | size_t GetLine(pid_t pid, unsigned long frame, unsigned long f_code) { 49 | const long f_trace = PtracePeek(pid, frame + offsetof(_frame, f_trace)); 50 | if (f_trace) { 51 | return static_cast( 52 | PtracePeek(pid, frame + offsetof(_frame, f_lineno)) & 53 | std::numeric_limits::max()); 54 | } 55 | 56 | const int f_lasti = PtracePeek(pid, frame + offsetof(_frame, f_lasti)) & 57 | std::numeric_limits::max(); 58 | const long co_lnotab = 59 | PtracePeek(pid, f_code + offsetof(PyCodeObject, co_lnotab)); 60 | 61 | int size = 62 | PtracePeek(pid, StringSize(co_lnotab)) & std::numeric_limits::max(); 63 | int line = PtracePeek(pid, f_code + offsetof(PyCodeObject, co_firstlineno)) & 64 | std::numeric_limits::max(); 65 | const std::unique_ptr tbl = 66 | PtracePeekBytes(pid, StringData(co_lnotab), size); 67 | size /= 2; // since we increment twice in each loop iteration 68 | const uint8_t *p = tbl.get(); 69 | int addr = 0; 70 | while (--size >= 0) { 71 | addr += *p++; 72 | if (addr > f_lasti) { 73 | break; 74 | } 75 | line += *p++; 76 | } 77 | return static_cast(line); 78 | } 79 | 80 | // This method will fill the stack trace. Normally in the C API there are some 81 | // methods that you can use to extract the filename and line number from a frame 82 | // object. We implement the same logic here just using PTRACE_PEEKDATA. In 83 | // principle we could also execute code in the context of the process, but this 84 | // approach is harder to mess up. 85 | void FollowFrame(pid_t pid, unsigned long frame, std::vector *stack) { 86 | const long f_code = PtracePeek(pid, frame + offsetof(_frame, f_code)); 87 | const long co_filename = 88 | PtracePeek(pid, f_code + offsetof(PyCodeObject, co_filename)); 89 | const std::string filename = PtracePeekString(pid, StringData(co_filename)); 90 | stack->push_back({filename, GetLine(pid, frame, f_code)}); 91 | 92 | const long f_back = PtracePeek(pid, frame + offsetof(_frame, f_back)); 93 | if (f_back != 0) { 94 | FollowFrame(pid, f_back, stack); 95 | } 96 | } 97 | 98 | // Locate _PyThreadState_Current within libpython 99 | unsigned long ThreadStateFromLibPython(pid_t pid, 100 | const std::string &libpython) { 101 | std::string elf_path; 102 | const size_t offset = LocateLibPython(pid, libpython, &elf_path); 103 | if (offset == 0) { 104 | std::ostringstream ss; 105 | ss << "Failed to locate libpython named " << libpython; 106 | FatalException(ss.str()); 107 | } 108 | 109 | ELF pyelf; 110 | pyelf.Open(elf_path); 111 | pyelf.Parse(); 112 | const unsigned long threadstate = pyelf.GetThreadState(); 113 | if (threadstate == 0) { 114 | throw FatalException("Failed to locate _PyThreadState_Current"); 115 | } 116 | return threadstate + offset; 117 | } 118 | 119 | } // namespace 120 | 121 | std::ostream &operator<<(std::ostream &os, const Frame &frame) { 122 | os << frame.file() << ':' << frame.line(); 123 | return os; 124 | } 125 | 126 | unsigned long ThreadStateAddr(pid_t pid) { 127 | std::ostringstream ss; 128 | ss << "/proc/" << pid << "/exe"; 129 | ELF target; 130 | target.Open(ss.str()); 131 | target.Parse(); 132 | 133 | // There's two different cases here. The default way Python is compiled you 134 | // get a "static" build which means that you get a big several-megabytes 135 | // Python executable that has all of the symbols statically built in. For 136 | // instance, this is how Python is built on Debian and Ubuntu. This is the 137 | // easiest case to handle, since in this case there are no tricks, we just 138 | // need to find the symbol in the ELF file. 139 | // 140 | // There's also a configure option called --enable-shared where you get a 141 | // small several-kilobytes Python executable that links against a 142 | // several-megabytes libpython2.7.so. This is how Python is built on Fedora. 143 | // If that's the case we need to do some fiddly things to find the true symbol 144 | // location. 145 | // 146 | // The code here attempts to detect if the executable links against 147 | // libpython2.7.so, and if it does the libpython variable will be filled with 148 | // the full soname. That determines where we need to look to find our symbol 149 | // table. 150 | std::string libpython; 151 | for (const auto &lib : target.NeededLibs()) { 152 | if (lib.find("libpython") != std::string::npos) { 153 | libpython = lib; 154 | break; 155 | } 156 | } 157 | if (!libpython.empty()) { 158 | return ThreadStateFromLibPython(pid, libpython); 159 | } 160 | // Appears to be statically linked, find the symbols in the binary 161 | unsigned long threadstate = target.GetThreadState(); 162 | if (threadstate == 0) { 163 | // A process like uwsgi may use dlopen() to load libpython... let's just 164 | // guess that the DSO is called libpython2.7.so 165 | // 166 | // XXX: this won't work if the embedding language is Python 3 167 | threadstate = ThreadStateFromLibPython(pid, "libpython2.7.so"); 168 | } 169 | return threadstate; 170 | } 171 | 172 | std::vector GetStack(pid_t pid, unsigned long addr) { 173 | // dereference _PyThreadState_Current 174 | const long state = PtracePeek(pid, addr); 175 | if (state == 0) { 176 | throw NonFatalException("No active frame for the Python interpreter."); 177 | } 178 | 179 | // dereference the current frame 180 | const long frame = PtracePeek(pid, state + offsetof(PyThreadState, frame)); 181 | 182 | // get the stack trace 183 | std::vector stack; 184 | FollowFrame(pid, frame, &stack); 185 | return stack; 186 | } 187 | } // namespace pystack 188 | -------------------------------------------------------------------------------- /src/pyframe.h: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #pragma once 17 | 18 | #include 19 | 20 | #include 21 | #include 22 | #include 23 | 24 | namespace pystack { 25 | 26 | class Frame { 27 | public: 28 | Frame() = delete; 29 | Frame(const Frame &other) : file_(other.file_), line_(other.line_) {} 30 | Frame(const std::string &file, size_t line) : file_(file), line_(line) {} 31 | 32 | inline const std::string &file() const { return file_; } 33 | inline size_t line() const { return line_; } 34 | 35 | private: 36 | std::string file_; 37 | size_t line_; 38 | }; 39 | 40 | std::ostream &operator<<(std::ostream &os, const Frame &frame); 41 | 42 | // Locate _PyThreadState_Current 43 | unsigned long ThreadStateAddr(pid_t pid); 44 | 45 | // Get the stack. The stack will be in reverse order (most recent frame first). 46 | std::vector GetStack(pid_t pid, unsigned long addr); 47 | } // namespace pystack 48 | -------------------------------------------------------------------------------- /src/pystack.cc: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #include 17 | 18 | #include 19 | #include 20 | #include 21 | #include 22 | 23 | #include "./config.h" 24 | #include "./exc.h" 25 | #include "./ptrace.h" 26 | #include "./pyframe.h" 27 | 28 | using namespace pystack; 29 | 30 | namespace { 31 | const char usage_str[] = "Usage: pystack [-h|--help] [-j|--json] PID\n"; 32 | 33 | void RunOnce(pid_t pid, unsigned long addr) { 34 | std::vector stack = GetStack(pid, addr); 35 | for (auto it = stack.rbegin(); it != stack.rend(); it++) { 36 | std::cout << *it << "\n"; 37 | } 38 | std::cout << std::flush; 39 | } 40 | } // namespace 41 | 42 | int main(int argc, char **argv) { 43 | double seconds = 0; 44 | double sample_rate = 0.01; 45 | for (;;) { 46 | static struct option long_options[] = { 47 | {"help", no_argument, 0, 'h'}, 48 | {"rate", required_argument, 0, 'r'}, 49 | {"seconds", required_argument, 0, 's'}, 50 | {"version", no_argument, 0, 'v'}, 51 | {0, 0, 0, 0}}; 52 | int option_index = 0; 53 | int c = getopt_long(argc, argv, "hjr:s:v", long_options, &option_index); 54 | if (c == -1) { 55 | break; 56 | } 57 | switch (c) { 58 | case 0: 59 | if (long_options[option_index].flag != 0) { 60 | // if the option set a flag, do nothing 61 | break; 62 | } 63 | break; 64 | case 'h': 65 | std::cout << usage_str; 66 | return 0; 67 | break; 68 | case 'r': 69 | sample_rate = std::stod(optarg); 70 | break; 71 | case 's': 72 | seconds = std::stod(optarg); 73 | break; 74 | case 'v': 75 | std::cout << PACKAGE_STRING << "\n"; 76 | return 0; 77 | break; 78 | case '?': 79 | // getopt_long should already have printed an error message 80 | break; 81 | default: 82 | abort(); 83 | } 84 | } 85 | if (optind != argc - 1) { 86 | std::cerr << usage_str; 87 | return 1; 88 | } 89 | long pid = std::strtol(argv[argc - 1], nullptr, 10); 90 | if (pid > std::numeric_limits::max() || 91 | pid < std::numeric_limits::min()) { 92 | std::cerr << "PID " << pid << " is out of valid PID range.\n"; 93 | return 1; 94 | } 95 | try { 96 | PtraceAttach(pid); 97 | const unsigned long addr = ThreadStateAddr(pid); 98 | const std::chrono::microseconds interval{ 99 | static_cast(sample_rate * 1000000)}; 100 | if (seconds) { 101 | auto end = 102 | std::chrono::system_clock::now() + 103 | std::chrono::microseconds(static_cast(seconds * 1000000)); 104 | for (;;) { 105 | try { 106 | RunOnce(pid, addr); 107 | } catch (const NonFatalException &exc) { 108 | // continue if we get a non-fatal exception 109 | std::cerr << exc.what() << std::endl; 110 | } 111 | auto now = std::chrono::system_clock::now(); 112 | if (now + interval >= end) { 113 | break; 114 | } 115 | PtraceDetach(pid); 116 | std::this_thread::sleep_for(interval); 117 | std::cout << "\n"; 118 | PtraceAttach(pid); 119 | } 120 | } else { 121 | RunOnce(pid, addr); 122 | } 123 | } catch (const FatalException &exc) { 124 | std::cerr << exc.what() << std::endl; 125 | return 1; 126 | } catch (const NonFatalException &exc) { 127 | std::cerr << exc.what() << std::endl; 128 | return 0; 129 | } catch (const std::exception &exc) { 130 | std::cerr << exc.what() << std::endl; 131 | return 1; 132 | } 133 | return 0; 134 | } 135 | -------------------------------------------------------------------------------- /src/pystring.cc: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #include "./pystring.h" 17 | 18 | #include 19 | #include 20 | 21 | #include 22 | 23 | #include "./config.h" 24 | 25 | namespace pystack { 26 | #if PY_MAJOR_VERSION == 2 27 | unsigned long StringSize(unsigned long addr) { 28 | return addr + offsetof(PyStringObject, ob_size); 29 | } 30 | 31 | unsigned long StringData(unsigned long addr) { 32 | return addr + offsetof(PyStringObject, ob_sval); 33 | } 34 | #elif PY_MAJOR_VERSION == 3 35 | unsigned long StringSize(unsigned long addr) { 36 | return addr + offsetof(PyVarObject, ob_size); 37 | } 38 | 39 | unsigned long StringData(unsigned long addr) { 40 | // this works only if the filename is all ascii *fingers crossed* 41 | return addr + sizeof(PyASCIIObject); 42 | } 43 | #else 44 | static_assert(false, "Unknown Python version."); 45 | #endif 46 | } // namespace pystack 47 | -------------------------------------------------------------------------------- /src/pystring.h: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #pragma once 17 | 18 | // This abstracts the string representation for py2/py3 19 | namespace pystack { 20 | unsigned long StringSize(unsigned long addr); 21 | unsigned long StringData(unsigned long addr); 22 | } // namespace pystack 23 | -------------------------------------------------------------------------------- /src/symbol.cc: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #include "./symbol.h" 17 | 18 | #include 19 | #include 20 | #include 21 | #include 22 | #include 23 | 24 | #include 25 | #include 26 | #include 27 | 28 | namespace pystack { 29 | void ELF::Close() { 30 | if (addr_ != nullptr) { 31 | munmap(addr_, length_); 32 | addr_ = nullptr; 33 | } 34 | } 35 | 36 | // mmap the file 37 | void ELF::Open(const std::string &target) { 38 | Close(); 39 | int fd = open(target.c_str(), O_RDONLY); 40 | if (fd == -1) { 41 | std::ostringstream ss; 42 | ss << "Failed to open target " << target << ": " << strerror(errno); 43 | throw FatalException(ss.str()); 44 | } 45 | length_ = lseek(fd, 0, SEEK_END); 46 | addr_ = mmap(nullptr, length_, PROT_READ, MAP_SHARED, fd, 0); 47 | while (close(fd) == -1) { 48 | ; 49 | } 50 | if (addr_ == MAP_FAILED) { 51 | std::ostringstream ss; 52 | ss << "Failed to mmap " << target << ": " << strerror(errno); 53 | throw FatalException(ss.str()); 54 | } 55 | 56 | if (hdr()->e_ident[EI_MAG0] != ELFMAG0 || 57 | hdr()->e_ident[EI_MAG1] != ELFMAG1 || 58 | hdr()->e_ident[EI_MAG2] != ELFMAG2 || 59 | hdr()->e_ident[EI_MAG3] != ELFMAG3) { 60 | std::ostringstream ss; 61 | ss << "File " << target << " does not have correct ELF magic header"; 62 | throw FatalException(ss.str()); 63 | } 64 | if (hdr()->e_ident[EI_CLASS] != ELFCLASS64) { 65 | throw FatalException("Currently only 64-bit ELF files are supported"); 66 | } 67 | } 68 | 69 | void ELF::Parse() { 70 | // skip the first section since it must be of type SHT_NULL 71 | for (uint16_t i = 1; i < hdr()->e_shnum; i++) { 72 | const Elf64_Shdr *s = shdr(i); 73 | switch (s->sh_type) { 74 | case SHT_STRTAB: 75 | if (strcmp(strtab(s->sh_name), ".dynstr") == 0) { 76 | dynstr_ = i; 77 | } 78 | break; 79 | case SHT_DYNSYM: 80 | dynsym_ = i; 81 | break; 82 | case SHT_DYNAMIC: 83 | dynamic_ = i; 84 | break; 85 | } 86 | } 87 | if (dynamic_ == -1) { 88 | throw FatalException("Failed to find section .dynamic"); 89 | } else if (dynstr_ == -1) { 90 | throw FatalException("Failed to find section .dynstr"); 91 | } else if (dynsym_ == -1) { 92 | throw FatalException("Failed to find section .dynsym"); 93 | } 94 | } 95 | 96 | std::vector ELF::NeededLibs() { 97 | // Get all of the strings 98 | std::vector needed; 99 | const Elf64_Shdr *s = shdr(dynamic_); 100 | const Elf64_Shdr *d = shdr(dynstr_); 101 | for (uint16_t i = 0; i < s->sh_size / s->sh_entsize; i++) { 102 | const Elf64_Dyn *dyn = reinterpret_cast( 103 | p() + s->sh_offset + i * s->sh_entsize); 104 | if (dyn->d_tag == DT_NEEDED) { 105 | needed.push_back( 106 | reinterpret_cast(p() + d->sh_offset + dyn->d_un.d_val)); 107 | } 108 | } 109 | return needed; 110 | } 111 | 112 | unsigned long ELF::GetThreadState() { 113 | const Elf64_Shdr *s = shdr(dynsym_); 114 | const Elf64_Shdr *d = shdr(dynstr_); 115 | for (uint16_t i = 0; i < s->sh_size / s->sh_entsize; i++) { 116 | const Elf64_Sym *sym = reinterpret_cast( 117 | p() + s->sh_offset + i * s->sh_entsize); 118 | const char *name = 119 | reinterpret_cast(p() + d->sh_offset + sym->st_name); 120 | if (strcmp(name, "_PyThreadState_Current") == 0) { 121 | return static_cast(sym->st_value); 122 | } 123 | } 124 | return 0; 125 | } 126 | } // namespace pystack 127 | -------------------------------------------------------------------------------- /src/symbol.h: -------------------------------------------------------------------------------- 1 | // This file is part of Pystack. 2 | // 3 | // Pystack is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU General Public License as published by 5 | // the Free Software Foundation, either version 3 of the License, or 6 | // (at your option) any later version. 7 | // 8 | // Pystack is distributed in the hope that it will be useful, 9 | // but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | // GNU General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU General Public License 14 | // along with Pystack. If not, see . 15 | 16 | #pragma once 17 | 18 | #include 19 | 20 | #include 21 | #include 22 | #include 23 | #include 24 | 25 | #include "./exc.h" 26 | 27 | namespace pystack { 28 | 29 | // Representation of a 64-bit ELF file. 30 | // 31 | // TODO: support 32-bit ELF files. One easiest way to do this would be to have 32 | // this class templated on the architecture where the 64-bit version uses the 33 | // Elf64_* structs and the 32-bit version uses the Elf32_* structs. Then another 34 | // function can inspect the ELF header and tell the caller which class they 35 | // should use. 36 | class ELF { 37 | public: 38 | ELF() : addr_(nullptr), length_(0), dynamic_(-1), dynstr_(-1), dynsym_(-1) {} 39 | ~ELF() { Close(); } 40 | 41 | // Open a file 42 | void Open(const std::string &target); 43 | 44 | // Close the file; normally the destructor will do this for you. 45 | void Close(); 46 | 47 | // Parse the ELF sections. 48 | void Parse(); 49 | 50 | // Find the DT_NEEDED fields. This is similar to the ldd(1) command. 51 | std::vector NeededLibs(); 52 | 53 | // Get the address of _PyThreadState_Current 54 | unsigned long GetThreadState(); 55 | 56 | private: 57 | void *addr_; 58 | size_t length_; 59 | int dynamic_, dynstr_, dynsym_; 60 | 61 | inline const Elf64_Ehdr *hdr() const { 62 | return reinterpret_cast(addr_); 63 | } 64 | 65 | inline const Elf64_Shdr *shdr(int idx) const { 66 | if (idx < 0) { 67 | std::ostringstream ss; 68 | ss << "Illegal shdr index: " << idx; 69 | throw FatalException(ss.str()); 70 | } 71 | return reinterpret_cast(p() + hdr()->e_shoff + 72 | idx * hdr()->e_shentsize); 73 | } 74 | 75 | inline unsigned long p() const { 76 | return reinterpret_cast(addr_); 77 | } 78 | 79 | inline const char *strtab(int offset) const { 80 | const Elf64_Shdr *strings = shdr(hdr()->e_shstrndx); 81 | return reinterpret_cast(p() + strings->sh_offset + offset); 82 | } 83 | 84 | inline const char *dynstr(int offset) const { 85 | const Elf64_Shdr *strings = shdr(dynstr_); 86 | return reinterpret_cast(p() + strings->sh_offset + offset); 87 | } 88 | }; 89 | } // namespace pystack 90 | --------------------------------------------------------------------------------